1. Field of the Invention
This invention relates to a simulation or test system for a computer network architecture, in particular on board an aircraft, and a corresponding simulation method.
2. Discussion of the Background
Nowadays the development of real systems is accomplished progressively with the aid of simulation systems. These systems make it possible to visualize and test projects in progress but also to have the latter evolve rapidly and at lower costs.
This is the case in particular in the aeronautical domain where simulation systems are used in which on-board equipment items, also called real computers, are integrated with modules simulating other equipment items.
In recent aircraft models, real computers are integrated into a digital network architecture of Ethernet type adapted for aeronautics and called ADCN (“Avionics Data Communication Network”) network using AFDX (“Avionics Full DupleX switched Ethernet”) technology. This network is made up of switches through which the computers communicate.
In this network, communications among computers are carried out in unconnected multicast (multicast) mode, that is to say without the recipient(s)' of the data acknowledging receipt to the sender. The paths that the various data take are organized in the form of virtual links (“Virtual Link” or “VL”). A virtual link is a logic path between a transmitting computer and n receiving computers.
These virtual links make it possible to define as many logic paths as necessary, mutually impermeable, and having guaranteed performances despite recourse to a common physical network. The combination of these links constitutes the logic topology of the network. In order to guarantee the required performances and meet the constraints for aeronautical certification, this logic topology is defined statically.
On the physical network, the data exchanged among the computers may pass in transit via one or more switches according to the physical topology of the ADCN network.
Document FR 2 868 567 presents a simulation system provided for such an avionic architecture. In this system, a simulation unit comprises models simulating real computers (a kind of software composed of functions of the simulated equipment items), and functions for AFDX communication with the real ADCN network to which it is connected. The simulation models are integrated into the ADCN digital network via the communication functions. By virtue of this integration, the simulation models communicate among themselves or with on-board equipment items, under conditions as close as possible to those found in the real aircraft.